Hmmm. If they're too leaky, they're act more like resistors than diodes and you won't even get to the 0.27V in-circuit because the other diode, the one that is supposed to be "off," will conduct too much current. Not an issue with hard limiters, like Distortion+, but definitely a concern with soft limiters like the BMP. One more thing, matching diodes in a BMP isn't really necessary because everything about that circuit except the diodes is asymmetrical.